Compositions containing bitumen and an olefin polymer

ABSTRACT

COMPOSITION CONTAINING BITUMEN, AN OLEFIN POLYMER, A BASIC SUBSTANCE AND SULFUR.

U.S. Cl. 260-235 AS 6 Claims ABSTRACT OF THE DISCLOSURE Compositions containing bitumen, an olefin polymer, a basic substance and sulfur.

The invention relates to compositions of matter containing bitumen and olefin polymers.

Such compositions are used for example as sealing compounds and for the production of sheeting and film.

It is known that polyethylene can be mixed with bitumen in all proportions (cf. US. Pat. 2,610,956). The molding material thus obtained is less brittle in the cold and has improved thermal stability under load as compared with purely bituminous molding material. Mixtures of bitumen and copolymers of acrylic esters and olefins have lower penetration values (cf. U.S. Pat. 3,249,567). These mixtures however tend to separate when stored which greatly limits their use, particularly for the production of film or sheeting.

It is an object of this invention to provide compositions of matter in which no separation occurs and which have improved mechanical properties, e.g. elasticity.

These objects are achieved by compositions of matter comprising (A) Bitumen having a penetration of from 10 to 300;

(B) Olefin polymers selected from the group consisting of homopolymers of ethylene, propylene and butylene, copolymers of ethylene with other ethylenically unsaturated monomers which copolymers contain more than 50% by weight of ethylene units, the ratio of the components (A) and (B) being from 0.1:1 to 120.1;

(C) A basic substance selected from the group consisting of an oxide, hydroxide, sulfide, carbonate, silicate of a metal of the first and second groups of the Periodic Table, an alkali metal salt and an alkaline earth metal salt of an organic acid having 2 to carbon atoms, nitrogen bases, ammonium hydrogen carbonate and ammonium polysulfide in an amount of from 0.5 to 50% by weight with reference to components (A) and (B); and

(D) Sulfur in an amount of from 0.5 to 30% by weight with reference to components (A) and (B).

The use of cement as a basic substance and also a content of sulfur and/or polysulfides or also of organic peroxides or compounds which yield oxygen in these compositions is particularly advantageous. The compositions are distinguished by very good elastic properties. Articles prepared therefrom have very good bonding properties and increased strength values, for example high tear resistance combined with high breaking extension.

All commercial natural and synthetic bitumens, asphalts, and tars, and also bitumens which have been blown with air and/or steam, are suitable for the compositions according to the invention. The preferred bitumens generally exhibit penetration values according to DIN 1995 of from 10 to 300 and a softening point (ring and ball) according to DIN 1995 of from 75 to 32 C. Low-viscosity bitumen oils, which can be distilled for example at a pressure of from 10* to 10- mm. at from 120 to 250 United States Patent 0 3,634,293 Patented Jan. 11, 1972 C. and which have only slight natural color, may however also be used. Very hard asphalts, for example asphalts freed from bitumen oils, are also suitable for making the compositions according to the invention.

Olefin polymers which are suitable for the compositions according to the invention include homopolymers of olefins having from two to four carbon atoms, for example high and low density polyethylenes, polypropylene and polybutene, copolymers of tat-olefins, particularly those having from two to four carbon atoms in the monomers, which contain more than 50% by weight of a-olefin units. All conventional comonomers which are copolymerizable with the Ot'OlCfiHS are suitable as comonomers.

It is preferred to use copolymers of ethylene with from 10 to 40% by weight of esters of acrylic or methacrylic acid with alcohols having from one to eight carbon atoms or vinylcarboxylic esters of carboxylic acids having two to six carbon atoms. Copolymers are particularly preferred which have been obtained by copolymerization of ethylene and tert-butyl or isopropyl acrylate or methacrylate, the conditions of manufacture of the polymer being such that some of the polymerized acrylic ester units result in the formation of free acid groups, for example by elimination of isobutylene. In this case the ethylene copolymers may contain 0.1 to 7 mole percent, preferably from 0.2 to 5 mole percent, of polymerized units of carboxylic acid, for example by weight of ethylene, 13% by weight of tert-butyl acrylate and 7% by weight of acrylic acid. Mixtures of olefin polymers, for example mixtures of homopolymers and copolymers or mixtures of copolymers or of homopolymers are also suitable.

The ratio of bitumen to olefin polymer in the compositions may be for example from 0.111 to 1:01

All conventional basic substances which in aqueous Solution or suspension give a pH of more than 7.5 are suitable as basic substances according to the invention; these include generally inorganic, preferably nonvolatile, substances such as oxides, hydroxides, sulfides, carbonates, silicates of metals of the first and second main groups of the Periodic System of the Elements, as for example sodium hydroxide, calcium oxide, calcium hydroxide, potassium sulfide, sodium carbonate and sodium silicate, and mixtures of oxides and/or hydroxides of the first and second main groups of the Periodic System of the Hements with silicates; cement is particularly suitable. Alkali metal and alkaline earth metal salts of organic acids having from two to thirty carbon atoms, alcoholates, phenolates, organic bases as for example nitrogenous basic compounds, urea, ammonium hydrogen carbonate and ammonium polysulfide are also suitable as basic substances.

The basic substances according to the invention may contain up to 30% by weight of water and are contained in the composition in amounts of from 0.5 to 50% by weight with reference to the olefin polymer and bitumen.

Moreover the compositions according to the invention may be modified in an advantageous way by adding sulfur in the form of molten sulfur, sulfur powder or colloidal sulfur and/or polysulfides in amounts of up to 30% by weight, preferably from 0.5 to 15% by weight, with reference to the bitumen and olefin polymer.

The advantageous properties of the compositions according to this invention are further improved by a content of orginic peroxides such as dicumyl peroxide, ditertbutyl peroxide, benzoyl peroxide, cyclohexanone peroxide, diacetyl peroxide, bitumen peroxides and/or hydroperoxides, and also compounds which yield oxygen in the compositions according to the invention at temperatures of from 20 to 300 C. Examples of such compounds are inorganic peroxy compounds such as peroxides, for example alkali metal peroxides; hydroperoxides, such as tetrahydronaphthalene hydroperoxide or decahydronaphthalene hydroperoxide; peroxide disulfates, and also compounds such as permanganates, chlorates, perchlorates and nitrates of alkali metals. The organic peroxides are used in amounts of from 0.01 to by weight, preferably 0.05 to 1% by weight, and the substances which yield ox gen preferably in amounts of from 0.01 to 1% by weight, with reference to the olefin polymer/ bitumen mixture.

Conventional inorganic fillers and/ or mineral inert pigments and the like such as slate powder, gypsum, chalk, talc, asbestos, glass powder, soot, colloidal silicic acid, particularly that obtained in the burning of silicon compounds, glass fibers, mineral wool, slag wool, bentonite, aluminas, limestone powder, dolomite powder, rock powder, titanium dioxide, metal titanates, zinc oxide, iron oxide, and chromium oxide, may also be added to the decompositions. Organic fillers such as wood flour, and/or cork powder and/or wood chips may also be added.

The compositions according to this invention may be prepared from the individual components by mixing them in conventional equipment, as for example in agitators, kneaders, extruders or on rollers.

It is advantageous to choose the following sequence in adding the individual components: bitumen, olefin polymer, to this mixture: basic substance (which may contain water), sulfur and the organic peroxide additive, and if desired fillers. It is also possible to mix all the components simultaneously. Mixing is usually carried out at temperatures which are above the softening temperature of the olefin polymer, i.e. at from about 100 to 300 C.,

' preferably at 120 to 250 C. The composition according to this invention is shaped by conventional methods by means of extruders, injection molding machines, presses or rollers followed by cooling to ambient temperature.

The compositions may be used as sealing compounds and for the production of elastic tack-free sheeting or film having very good heat-sealing and embossing properties. The compositions are considerably paler than comparable prior art materials.

The tear resistance of shaped articles therefrom is much higher than in the case of exclusively bituminous olefin polymer compositions and there is no separation problem in storage.

The invention is illustrated by the following examples. The parts and percentages specified in the examples are parts by weight and percentages by weight.

EXAMPLE 1 48.5 parts of bitumen (penetration value 80, breaking point 9 to 1l C. according to DIN 1995) is heated to 180 C. in a heatable kneader and 48.5 parts of a copolymer of 80 parts of ethylene and parts of butyl acrylate and 1.5 parts of sulfur are dissolved in the molten bitumen. A mixture of 1.5 parts of cement (for example portland cement) and 0.1 part of benzoyl peroxide are introduced into the mixture. A constant viscosity has been set up within a few minutes. The melt is pressed into a sheet having a thickness of 0.5 mm. The sheet has a midgray color. No oily exudation whatever occurs upon storage.

Test according to DIN 53,371 (tensile test):

ultimate tensile strength: 68 kg./crn breaking extension: 800% Without the additions according to this invention, a deep black sheeting is obtained which becomes tacky upon storage and has an ultimate tensile strength of kg./cm. at a breaking extension of 800%.

EXAMPLE 2 (a) 50 parts of bitumen (penetration 80, breaking point 9 to 11 C. according to DIN 1995) and 50 parts of a copolymer of 80 parts of ethylene and 20 parts of butyl acrylate are mixed for about ten minutes at 180 C. as in Example 1.

(b) 25 parts of cement (for example portland cement) which contains about 10% of water of hydration is added to parts of the mixture described under (a) and the whole mixed for about ten minutes at 180 C.

(c) 25 parts of slate powder is added at 180 C. to 75 parts of the mixture described under (a) and mixed for about ten minutes.

(d) 5 parts of sulfur and 5 parts of cement which contains about 10% of water of hydration are added at 180 C. to parts of the mixture described under (a) and mixed for ten minutes.

After the mixtures have cooled, a 0.5 mm. sheet is prepared from each of them and tested according to DIN 53,371 (tensile test) and the behavior on storage is observed. The results are given in the following table in which the following abbreviations are used: Addn addition (in percent by weight) TTS=test of tensile strength according to DIN 53,371 in kg./cm.

40 parts of a copolymer of 90 parts of ethylene and 10 parts of vinyl acetate is mixed at a temperature of 150 to 180 C. with 60 parts of bitumen (penetration 200, breaking point 9 C. according to DIN 1995). The melt is pressed into strands, cooled to room temperature and granulated so that granules having a particle size of 5 mm. is obtained. If these granules are stored for from some hours to days, they stick together and superficial oily exudation appears. To obtain free-flowing granules, 5 parts of a powdered mixture of 14 parts of cement (for example Portland cement), 10 parts of sulfur powder, 0.01 part of diacetyl peroxide and 1 part of water is added to parts of granules.

Mixing is carried out in an extruder at from to C. and shaping by means of a sheeting die. A blue gray dry and rubberlike sheet is obtained. Tests according to DIN 53,371: tensile strength: 20 kg./cm. breaking extension: 500% Without the said additive according to the invention, a tensile strength of 12 kg./cm. at a breaking extension of 450% is obtained.

EXAMPLE 4 The procedure of Example 1 is followed and 40 parts of bitumen (penetration 200, breaking point 9 C.) and 60 parts of a copolymer of 90 parts of ethylene and 10 parts of vinyl propionate are mixed. 20 parts of calcium hydroxide, 1.5 parts of sulfur and 5 parts of dicumyl peroxide are introduced into this mixture at 220 C. After a residence time of two minutes the mixture is cooled to 130 C. and extruded through an annular die having a diameter of 2 cm. and a die width of 2 mm. A non-tacky hose having a matt black color is obtained which permanently withstands a water pressure of 4 atmospheres gauge at temperatures of up to 40 C. and exhibits no exudation whatever upon storage. Tests according to DIN 53,371:

ultimate tensile strength: 90 kg/cm? breaking extension: 750% Comparison without additive according to the invention:

ultimate tensile strength: 65 kg./cm. breaking extension: 800% EXAMPLE 5 The procedure of Example 4 is followed, 70 parts of bitumen (penetration 25) and 30 parts of a copolymer of 75 parts of ethylene and 25 parts of butyl acrylate being placed in a kneader. parts of cement (for example portland cement) containing 7.5% water of hydration, 3 parts of sulfur and 3.5 parts of ditert-butyl peroxide is incorporated into this mixture. Mixing takes place in a closed kneader for a residence time of two minutes at 210 C. The mixture is cooled to 100 C., extruded into strands and granulated. Deep black granules are obtained which remain free-flowing over many months and do not show any oily exudation on storage. Sheeting prepared therefrom exhibits an ultimate tensile strength of 12 kg./cm. at a breaking extension of 500% (tests according to DIN 53,371). Without the additive according to the invention a tacky product is obtained which shows oily exudation and has an ultimate tensile strength of 7.5 kg./cm. at a breaking extension of 600%.

EXAMPLE 6 A mixture of 10 parts of sulfur, 40 parts of calcium hydroxide, 30 parts of chalk powder, 02 part of dibenzoyl peroxide and 7 parts of water is added at a temperature of 180 C. to a mixture of 90 parts of bitumen and 10 parts of a copolymer of of isobutyl acrylate, 5% of acrylic acid and 75% of ethylene. The mixture is kept at 180 C. for ten minutes, cooled to 120 C. and poured onto a paper surface treated with a parting agent. A gray sheet is obtained which is not tacky, which can be stored without separation phenomena and which may be granulated direct for example by means of shears at C. The ultimate tensile strength (according to DIN 53,371) is 10 kg./cm. at a breaking extension of 300%. Without the additive according to the invention, a product is obtained which separates when stored and has an ultimate tensile strength of 5 kg./cm. at a breaking extension of 350%.

EXAMPLE 7 In the manner described in Example 1, 50 parts of bitumen (penetration 80) and 50 parts of a copolymer of 85 parts of ethylene and 15 parts of butyl acrylate are mixed at 200 C. with 5 parts of sulfur, 2.5 parts of cement (12% water of hydration) and 5 parts of chalk, 0.1 part of potassium bichromate or 0.1 part of sodium chlorate or 0.1 part of potassium permanganate is added for each 100 parts of this mixture and the whole mixed for about ten minutes. Sheet obtained from these mixtures is pale gray, does not show any oily exudation [whatever on storage and according to DIN 53,371 has ultimate tensile strengths of from 55 to 65 kg./cm. at breaking extensions of from 700 to 800%. Without the additive according to the invention, black sheeting is obtained which exhibits oily exudation on storage and has ultimate tensile strengths of 48 kg/cm. at a breaking extension of 800%.

EXAMPLE 8 The procedure of Example 6 is followed but parts of yellow ammonium sulfide (10% S) or finely powdered sodium polysulfide is used in the mixture instead of sulfur. After casting, sheeting is obtained which can be stored without separation phenomena and which has a pale gray color. Ultimate tensile strength 8 kg./cm. breaking extension 400%. Without the additives according to this invention the ultimate tensile strength is 5 leg/cm. and the breaking extension 350%; there is oily exudation on storage.

EXAMPLE 9 The procedure of Example 6 is followed but a mixture of 30 parts of talc, 10 parts of sodium silicate and 5 parts of Water is used in the mixture instead of parts of calcium hydroxide. Pale gray granules are obtained which remain free-flowing over many months. Tests. according to DIN 53,371:

6 ultimate tensile strength: 13 kg/cm. breaking extension: 250% EXAMPLE 10 40 parts of bitumen (penetration 25), 200 parts of polyethylene (density 0.964 g./cm.; melt index 0.15 (190/20) 6 parts of sulfur and 1.5 parts of zinc oxide are homogenized in a heatable kneader at 180 to 190 C. in the course of two to five minutes. The homogeneous melt is forced through a sheeting die to form 2-mm. sheeting. When the sheeting is tested according to DIN 53,455 a tensile strength of 220 kg./cm. an ultimate tensile strength of 250 kg./cm.2 and a breaking extension of 800% are found. The composition has a pale blue gray color and is suitable for the production of tubes.

EXAMPLE ll tensile strength: 75 kg./cm. ultimate tensile strength: kg./cm. breaking extension: 550% EXAMPLE 12 As in Example 10, the components (a) to (0) given below are homogenized at a temperature of 190 C.:

50 parts of polypropylene having a melt index of 1.2

50 parts of bitumen having a penetration of 80, and 1 part of sodium carbonate as under (a) but with the addition of 0.2 part of dibenzoyl peroxide 47 parts of polypropylene having a melt index of 1.2 47 parts of bitumen having a penetration of 80, 15 parts of sulfur, 2 parts of portland cement, and 0.05 part of dibenzoyl peroxide Sheeting is made by a known method from the mixtures (a) to (c) and this is tested according to the conditions laid down in DIN 53,455, the following values being obtained:

Sheeting Tensile strength in kgJcmfl Ultimate tensile strenght kgJcm. 113 140 15) Breaking extension in percent 200 300 50 The mixtures (a) and (b) give products which are deep black, which have a high surface gloss and do not agglomerate. Mixture (c) has the properties of a press molding material and has a blue grey appearance.

EXAMPLE 13 120 parts of bitumen (penetration 80), 80 parts of polyethylene (density 0.96 g./cc.; melt index 5.2 (190/ 20)), 25 parts of sulfur and 0.5 part of morpholine are mixed in a heatable kneader at to C. Sheeting is prepared from the homogeneous mixture. According to DIN 53,455 it has a tensile strength of 100 kg./cm. an ultimate tensile strength of 115 kg./cm. and a breaking extension of 870% Granules of this mixture are unaltered in being freeflowing, dry and repeatedly fusible even after having been stored for one year in a stack on a pallet. Sheeting from this mixture does not exhibit any aging phenomena after exposure to the weather for one year.

EXAMPLE 14 180 parts of polyethylene (density 0.953 g./cc.; melt index 1.8 (190/20)), 20 parts of bitumen, 6 parts of sulfur, 1 part of phenyl-fi-naphthylamine and 3 parts of soot are mixed at from 190 to 200 C. The homogeneous mixture is granulated. The granules can be repeatedly melted and do not agglomerate when stored. They are particularly suitable for the production of tubes.

Sheeting prepared from this mixture has according to DIN 53,455 a tensile strength of 270 kg./cm. an ultimate tensile strength of 360 kg./cm. and a breaking extension of 850%.

EXAMPLE 15 As described in Example 14, 180 parts of bitumen (penetration 25), 20 parts of polyethylene (density 0.963 g./cc.; melt index 5.5 (190/2)), 35 parts of sulfur, 3 parts of zinc oxide and 1 part of di-fl-naphthyl-p-phenylenediamine are mixed together. From this mixture, sheeting having a thickness of 1 mm. is cast. When tested according to DIN 53,455 it has an ultimate tensile strength of 15 kg./cm. and a breaking extension of 100%. The mixture can be used as plastic sheeting for sealing purposes or as a sealing compound.

I claim:

1. A composition of matter derived by heating at a temperature of 100300 C. of a mixture consisting essentially of (A) bitumen having a penetration of from to (B) olefin polymers selected from the group consisting of homopolymers of ethylene, propylene and butylene, copolymers of ethylene with other ethylenically unsaturated monomers which copolymers contain more than 50% by weight of ethylene units, the ratio of the components (A) and (B) being from 0.1:1 to 1:0.1;

(C) a basic substance selected from the group consisting of an oxide, hydroxide, sulfide, carbonate, silicate of a metal of the first and second groups of the Periodic Table, an alkali metal salt and an alkaline earth metal salt of an organic acid having 2 to 30 carbon atoms, nitrogen bases, ammonium hydrogen carbonate and ammonium polysulfide in an amount of from 0.5 to 50% by Weight, with reference to components (A) and (B); and (D) sulfur in an amount of from 0.5 to 30% by Weight with reference to components (A) and (B).

2. A composition of matter as claimed in claim 1 in which component (C) is cement, morpholine, di-fi-phenylene diamine, phenyl-B-naphthylamine or polyethyleneimine.

3. A composition of matter as claimed in claim 1 in which component (B) is a terpolymer consisting of by weight of ethylene units, 13% by weight of tert-butyl acrylate units and 7% by weight of acrylic acid units.

4. A composition of matter as claimed in claim 1 which also contains a filler.

5. A composition of matter derived by heating at a temperature of -300 C. of a mixture consisting of (A) bitumen having a penetration of from 10 to (B) olefin polymers selected from the group consisting of homopolymers of ethylene, propylene and butylene, copolymers of ethylene with other ethylenically unsaturated monomers which copolymers contain more than 50% by weight of ethylene units, the ratio of the components (A) and (B) being from 0.1:1 to 110.1;

(C) a basic substance selected from the group consisting of an oxide, hydroxide, sulfide, carbonate, silicate of a metal of the first and second groups of the Periodic Table, an alkali metal salt and an alkaline earth metal salt of an organic acid having 2 to 30 carbon atoms, nitrogen bases, ammonium hydrogen carbonate and ammonium polysulfide in an amount of from 0.5 to 50% by Weight, with reference to components (A) and (B); and

(D) sulfur in an amount of from 0.5 to 30% by weight with reference to components (A) and (B) and (E) a compound selected from the group consisting of di-cumyl-peroxide, di-tert-butyl peroxide, benzoyl peroxide, diacetyl peroxide, cyclohexanone peroxide, peroxides of bitumen, hydroperoxides of decahydronaphthalene and tetrahydronaphthalene, peroxydisulfates, permanganates and nitrates of alkali metals in an amount of from 0.01 to 5% by weight, with reference to components (A) and (B).

6. A composition of matter as claimed in claim 5 in which component (C) is cement, morpholine, di-fi-naphthyl-[i-phenylene diamine, phenyl-fi-naphthylamine or polyethyleneimine.

References Cited UNITED STATES PATENTS 8/1939 Patrick 2602.8 3/1966 Vigneault 260--28.5

OTHER REFERENCES MORRIS LIEBMAN, Primary Examiner R. ZAITLEN, Assistant Examiner US. Cl. X.R.

@gggg UNITED STATES PATENT mm CFERTIFICATE OF CURREC'HU' Patent No. 3, 5 ,295 I Dated January 11, 1972 Invencor(s) BOnitZ It is certified that error appears in the above-identified-patent and that said Letters, Patent arehereby corrected as shown below:

Column 2 line 64, "orgini d should read organic Column 6, liLne 59, "strenght" should read strength Column v7, lines 57-58, "di-fl-phenylene" should read I di-vfl-naphthyl-6-phenylepe Signed and sealed this 22nd day of August 1972.

(SEAL) Attost:

EDWARD M.FLETGHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

